Flail knife structure

ABSTRACT

A knife, for a flail-mower, comprises a flat elongated member bent transversely intermediately of its ends to provide a shank p  and a cutting portion joined at a corner having inner and outer sides, a reinforcing rib being formed integrally, by upstanding, across the inner side of the corner.  All three sides of the cutting portion of the knife are sharpened so that the knives, which are mounted back-to-back in pairs during use, can be reversed to bring the opposite lateral edges into the leading position.

1957 R. w. WOODRING 3,335,555

FLAIL KNIFE STRUCTURE Filed Dec. 2, 1964 t /l 9 r 22 I I} 26 h 20 2g 15 1a 26" i;

Foerg W 775011221239 United States Patent M 3,335,555 FLAIL KNIFE STRUCTURE Robert W. Wood'ring, La Grange, Ill., assignor to International Harvester Company, Chicago, Ill., a corporation of Delaware Filed Dec. 2, 1964, Ser. No. 415,337 1 Claim. (Cl. 56294) ABSTRACT OF TIE DISCLOSURE A flail blade with an upset ri'b between shank and cutter portion and front and rear edge portions on the cutter portion diverging away from rib and bevels on these portions diagonal to their front and rear sides.

This invention is directed to a flail structure commonly used in mowers of a type employing flails pivotally mounted on a carrier which is rotatable at high speed about a horizontal axis for sweeping the cutting edges of the flails into the vegetation for cutting the same and relates more particularly to an improved type of flail construction.

The structure of the flail under consideration is commonly used in mowers which employ grass-cutting flails pivotally mounted upon a rotatable carrier for swinging radially outwardly from said carrier when it is rotated at high speed, thus enabling sharpened end portions of the flail to chop the vegetation into short pieces and scatter the same upon the ground. In mowers which are used in heavy duty service where the flails are particularly abused, such as in highway use, the blades heretofore used were quickly broken and particularly the cutting end portions thereof would break off after striking debris extending along the highway within the vegetation, such debris not having been observed by the operator or being deliberately run into because of carelessness or disregard by the operator. Specifically, the type of flails of which the present structure is an improvement, are disclosed in US. Patent No. 2,590,065 wherein the knife is formed from a flat piece of elongated metal, such as a metal strip, and has a flat shank portion which is presented edgewise to the material and an outer end cutting portion which is angled laterally with respect to the shank portion, the outer end portion having sharpened leading and trailing edges. In the prior art structures the outer end portions would break off from the shank portions at the juncture therebetween which juncture would frequently be weakened because of rupturing of the metal during the bending operation or because of fatigue failures.

A general object of the invention is to provide a novel and improved type of cutter flail or knife provided with a cutter end portion turned upwardly from a pivotally supported shank portion wherein the juncture between the outer end portion and the shank portion is substantially reinforced by the provision of a rib structure which is deformed from the corner formed at the juncture.

A further object of the invention is to provide in the knife structure heretofore described, a novel rib structure interconnecting the shank and the end portions, said rib providing an upwardly directed rounded contour to facilitate discharge of the material from the area of the juncture to minimize the wear therealong.

A still further object of the invention is the provision of a knife structure wherein the rib is disposed within the included corner between the shank and the cutting end portions of the knife, said rib functioning to develop air currents in a direction laterally outwardly from the juncture whereas to blow away the material abrading the juncture.

A still further object of the invention is to provide a 3,335,555 Patented Aug. 15, 1967 novel reinforced knife construction wherein the reinforcement in the juncture between the shank and the cutting end portions is developed by upsetting the parent metal at the corner whereby developing a corner at the juncture of superior strength at minimum cost.

A still further object of the invention is to provide a knife structure which serves as a deflector at the juncture for material being cut so as to cause the material to flow axially with respect to the rotor so that the material may be intercepted several times by the succeeding knives.

These and other objects and advantages inherent in and encompassed by the invention become more readily apparent from the specification and the drawings, wherein:

FIGURE 1 is a front elevational view of a mower unit with only part of the flails or knives and of the rotor carrying the same shown in detail, this view being drawn on a reduced scale with respect to that used in the higher numbered figures;

FIGURE 2 is a side elevational view of one flail knife;

FIGURE 3 is a front edge elevational view thereof;

FIGURE 4 is a cross sectional view taken substantially on the line 4-4 of FIGURE 3; and

FIGURE 5 is a rear elevational view of one of the knives.

Describing the invention in detail and having particular reference to the drawings, there is shown in FIGURE 1 a mower structure generally designated 2 which comprises a housing 3 including an arcuate top cover 4, a suitable hitch or handle 5 suitably connected to the cover 4 for propelling the mower along the ground. The mower 2 includes a pair of vertical side members or end plates 6 and 7 which support journal bearings 8 and 9 for mounting a rotor shaft 10. The shaft 10 is connected to a source of transmission and herein shown as a pulley 12 which may be connected by any suitable belt drive to a suitable power source such as a separate engine or to the power source of the towing vehicle, if such is used. The side supports 6 and 7 also mount a shaft 14 adjacent to their lower ends and the shaft 14 rotatably supports a groundengaging or traversing means herein shown in the form of a roller 15. Thus, the rotor is suitably gauged and propelled along the ground. The rotor, in addition to the shaft 10, comprises a plurality of connector plates 18 which extend radially with respect to the shaft 10 and are connected thereto and constrained for rotation therewith. Each of these connector plates 18 is suitably apertured and supports mounting pivots or rods 20 and the rods are secured against axial displacement by means of cotter keys 22. Each rod is provided with suitable spacer sleeves 24 between which are disposed at suitable intervals, in order to provide coverage along the entire axial extent of the rotor, a plurality of pairs of knives 26, 26.

Each knife or flail 26 is formed of flat strip metal elongated and substantially rectangular in elevation. Each flail comprises a flat shank portion 28 with a transverse opening or aperture 29 at its inner end by means of which the flail is sleeved over the mounting shaft or rod 20 for swinging movement about the axis of the carrier and for radial outward extension pursuant to rotation of the rotor. The shank portion is connected to an outwardly extending or laterally extending outer end cutting portion 32 which projects transversely of the shank portion 28. It will be realized that the blade is presented edgewise with respect to the cuttingdirection or rotational direction and depending on the position of the blade on the rotor, and the direction of rotation and only for purpose of description, the edge 33 is assumed to be the front edge and the edge 34 the rear edge. The end of the shank portion comprising the pivotal pin 29 will be termed the inner end 35 and the end of the shank portion where it joins or merges into the juncture or corner 36 with the cutting portion will be termed the outer end portion 38 of the shank portion.

It will be observed that the outer end cutting portion 32 extends outwardly of the outer side or face 40 of the shank portion 28 and extends at an acute angle of departure designated by the are a from the plane of the shank portion 28. This angle of departure is sufficiently restricted to accommodate centrifugal discharge of cut material along the outwardly turned inner face 44 of the end portion and over the free end 45 thereof. The angle a is preferably in the vicinity not exceeding 65 for enabling the flail end portion 32 to cut a reasonably wide swath while avoiding accumulations of vegetation upon the end portion. It will be noted that the forward and rear edges of the end portion are beveled outwardly from the inner face 44 to provide sloping front and rear levels 46 and 47, it being understood that when the blade is positioned at the left side of the pair as shown in FIGURE 1, the edge 46 will do the cutting and the same blade after the edge 46 has been chipped, worn or in any other way deteriorated, the blade at the left side will be turned and placed on the right side of the flail and the one on the right side will be turned and placed on the left side. Therefore, the edges 47 then will become the cutting edges.

It will be noted from a consideration, particularly of FIGURES 2, 3 and 4 that the junture 36 forms an interior corner 50. At this corner there is provided by upsetting from the exterior corner 51 a rib structure 52 disposed substantially medially between the front and rear edges 33 and 34 of the blade. The rib has a substantially extent inwardly from the outer end 38 of the shank portion 28 and outwardly from the inner end portion 54 of the cutting portion 32 of the knife. In crossconfiguration the rib with the two portions 28, 32 provides a triangular structure as the blade is viewed edgewise. The rib 52 is upset from the parent metal constituting the portions 28 and 32 and provides a concavity 58 within the external corner and provides a convex contour into the interior of the corner. The material-engaging deflector portions 60, 62 are developed and these present outwardly directed convex surfaces 63-, 64 which merge into a curvilinear apex 65 forming a ridge spanning the end portions 38, 54 of the shank and the cutting portions of the knife. Thus, it will become apparent that upon the knife rotating in one direction, the surface 63 will cause the material, which would normally ride along the interior corner 50 to sling laterally outwardly from the corner and thus, the portion of corner of the :blade rearwardly or behind the surface 63 would then not be abraded by the material. Conversely, when the 'blade is turned in the opposite direction or mounted so that its rear edges are in effect the front edge, then the surface 64 serves the same purpose to protect the ramp or the portion and area therebehind. Thus, the knife is prevented from quickly wearing through along the entire extent of the interior corner. Furthermore, the diagonal rib or bracing developed by the upsetting rigidifies the critical area of these portions to absorb heavy impacts.

It will be noted from a consideration of FIG. 4 that the front and rear edge portions 60a and 62a diverge downwardly from the rib portions 63, 64 respectively and at their lower edges provide bevel faces 60b and 62b which extend diagonally cross-wise of the portions 60a and 62a respectively and thus are wider than the thicknesses of these portions 60a and 62b. The increased crosssectional areas along these bottom faces thus obtain the advantage of utilizing more material to increase the life of the cutting edges.

It will be observed that applicant has used the constructions heretofore shown in the aforementioned Patent 2,590,065 and other manufacturers have used such construction in numerous machines. The problem has existed during all this time and no ready solution had 'been found until the advent of the instant invention.

It will be evident that a novel, strong and inexpensive new structure has been provided which not only retains the good qualities of such knives heretofore available but which additionally provides the features heretofore enumerated.

What is claimed is:

A flail having a generally flat vertical shank segment and a diagonally outwardly and downwardly extending end segment, said segments merged in an integral junction forming a corner, said segments having leading and trailing edge portions, rib means within the corner disposed generally medially between said edge portions and providing a convex structure within the corner serving to direct movement of material outwardly of the junction and said edge portions of the end segment converging at said rib means toward said rib means and having upper and lower surfaces extending diagonally downwardly outwardly from said rib means, and said edge portions having bottom bevels extending diagonally cross-sectionally of the edge portions from the respective top surfaces to the respective bottom surfaces thereof and providing bottom faces on the bevels wider than the thickness of said portions, said faces disposed in substantially coplanar relationship.

References Cited UNITED STATES PATENTS 2,070,041 2/ 1937 Coe 30-318 2,151,577 3/ 1939 'Withington 30-3 18 2,590,065 3/1952 Mott.

ABRAHAM G. STONE, Primary Examiner.

ANTONIO F. GUIDA, Assistant Examiner. 

